4G/5G Core Interworking

ABSTRACT

Systems, methods and computer software are disclosed for 4G and 5G core interworking. In one embodiment a HetNet gateway (HNG) is disclosed. The HNG includes a virtual 4G core; a virtual 5G core; an interface to a core network; an interface to a 4G Radio Access Network (RAN); and an interface to a 5G RAN. The HNG provides interworking 4G to 5G such that a 5G RAN works with a 4G core.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/022,077, filed Sep. 15, 2020, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Pat. App. No. 62/900,647, filed Sep. 15,2019, titled “4G/5G Core Interworking”, each of which is herebyincorporated by reference in its entirety for all purposes. The presentapplication hereby incorporates by reference U.S. Pat. App. Pub. Nos.US20110044285, US20140241316; WO Pat. App. Pub. No. WO2013145592A1; EPPat. App. Pub. No. EP2773151A1; U.S. Pat. No. 8,879,416, “HeterogeneousMesh Network and Multi-RAT Node Used Therein,” filed May 8, 2013; U.S.Pat. No. 8,867,418, “Methods of Incorporating an Ad Hoc Cellular NetworkInto a Fixed Cellular Network,” filed Feb. 18, 2014; U.S. patentapplication Ser. No. 14/777,246, “Methods of Enabling Base StationFunctionality in a User Equipment,” filed Sep. 15, 2016; U.S. patentapplication Ser. No. 14/289,821, “Method of Connecting Security Gatewayto Mesh Network,” filed May 29, 2014; U.S. patent application Ser. No.14/642,544, “Federated X2 Gateway,” filed Mar. 9, 2015; U.S. patentapplication Ser. No. 14/711,293, “Multi-Egress Backhaul,” filed May 13,2015; U.S. Pat. App. No. 62/375,341, “S2 Proxy for Multi-ArchitectureVirtualization,” filed Aug. 15, 2016; U.S. patent application Ser. No.15/132,229, “MaxMesh: Mesh Backhaul Routing,” filed Apr. 18, 2016, eachin its entirety for all purposes, having attorney docket numbersPWS-71700US01, 71710US01, 71717US01, 71721US01, 71756US01, 71762US01,71819US00, and 71820US01, respectively. This application also herebyincorporates by reference in their entirety each of the following U.S.Pat. applications or Pat. App. Publications: US20180242396A1(PWS-72501US02); US20150098387A1 (PWS-71731US01); US20170055186A1(PWS-71815US01); US20170273134A1 (PWS-71850US01); US20170272330A1(PWS-71850US02); and Ser. No. 15/713,584 (PWS-71850US03). Thisapplication also hereby incorporates by reference in their entirety U.S.patent application Ser. No. 16/424,479, “5G InteroperabilityArchitecture,” filed May 28, 2019; and U.S. Provisional Pat. ApplicationNo. 62/804,209, “5G Native Architecture,” filed Feb. 11, 2019.

BACKGROUND

5G is the next generation Mobile Communication technology following the4G/LTE. 3GPP has been working on defining the standards for 5G as partof 3GPP Rel 15 and 16. Starting 1G and then followed by 2G, 3G and 4G,each generation has the laid the foundation for the next generation inorder to cater to newer use cases and verticals. 4G was the firstgeneration that introduced flat architecture with all-IP architecture.4G enabled and flourished several new applications and use case. 5G isgoing to be not just about higher data rates but about total userexperience and is going to cater to several new enterprise use caseslike Industrial automation, Connected Cars, Massive IOT and others. Thiswill help operators to go after new revenue opportunities.

Launching 5G network will need significant investment as it will needRAN and Packet Core upgrade. 3GPP has defined a new 5G NR and new 5GCore. Eventually all the operators will want to head towards a complete5G network coverage with the new 5G Standalone Core, given the severalnew features and capabilities that the new 5G Standalone network bringsin. But given the significant cost involved, 3GPP has defined number ofdifferent intermediate solutions that can provide gradual migration fromcurrent 4G network to the eventual native 5G network.

SUMMARY

3GPP has proposed multiple options to enable operators to launch 5G in agraceful manner. One option is referred to as Non-Stand Alone (NSA)while another option is referred to a Stand Alone (SA).

In one embodiment a system for providing a 5G mobile network isdescribed. The system includes a 4G base station, a 5G base station, avirtualization server (the virtualization server further comprising avirtual 4G core, a virtual 5G core, and an Interworking Function (IWF)in communication with the 4G and 5G base stations and with the virtual4G and 5G cores), and either a 4G core (an Evolved Packet Core (EPC)) ora 5G core (NGC) in communication with the virtualization server. The IWFmay function as an Access and Mobility Management Function (AMF) to the5G SA base station and functions as a Mobility Management Entity (MME)towards the EPC.

In another embodiment, a method for 4G and 5G core interworking isdescribed. The method includes providing a HetNet gateway (HNG), the HNGcomprising: a virtual 4G core; a virtual 5G core; an interface to a corenetwork; an interface to a 4G Radio Access Network (RAN); and aninterface to a 5G RAN. The method further includes interworking, by theHNG, 4G to 5G such that a 5G RAN works with a 4G core.

In another embodiment, a non-transitory computer-readable mediumcontaining instructions for 4G and 5G core interworking is described,The computer readable medium includes instructions which, when executed,cause a HetNet Gateway (HNG) perform steps including providing a virtual4G core, a virtual 5G core, an interface to a core network, an interfaceto a 4G Radio Access Network (RAN), and an interface to a 5G RAN; andproviding interworking 4G to 5G such that a 5G RAN works with a 4G core.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a 5G Non-Standalone (NSA) network.

FIG. 2 is a diagram showing a 5G Standalone (SA) network.

FIG. 3 is a diagram showing a migration path from 4G to 5G.

FIG. 4 is a system diagram of a 4G core with a 4G RAN and a 5G RAN, inaccordance with some embodiments.

FIG. 5 is a system diagram showing an HNG between the 4G core and a 4GRAN and a 5G RAN, in accordance with some embodiments.

FIG. 6 is a system diagram showing an HNG between the 4G core and a 4GRAN and a 5G RAN, in accordance with some embodiments.

FIG. 7 is a system diagram showing an HNG between the 4G core with a 5Gcore and a 4G RAN and a 5G RAN, in accordance with some embodiments.

FIG. 8 is a schematic network architecture diagram for various radioaccess technology core networks.

FIG. 9 is an enhanced eNodeB for performing the methods describedherein, in accordance with some embodiments.

FIG. 10 is a coordinating server for providing services and performingmethods as described herein, in accordance with some embodiments.

DETAILED DESCRIPTION

FIG. 1 shows a prior art 5G Non-Standalone (NSA) solution 100. Thissolution includes an EPC 101 in communication with an eNB 102 and a gNB103. The eNB102 and the gNB 103 are in communication with each other.Also shown is a 5G NSA UE device 104 in communication with the eNB andthe gNB. This solution allows operators to launch 5G service byanchoring 5G gNodeB to the existing EPC packet core. Thus, it helpsoperators to launch 5G service with minimal disruption to the existingpacket core and leverage their existing investment in the current 4Gnetwork for 5G as well. 5G NSA needs 5G NSA compatible 5G devices whichuse 4G NAS to communicate with EPC Packet Core.

FIG. 2 shows different 5G Standalone (SA) solutions. Solution 200 isreferred to as Option 5, solution 201 is referred to as Option 7,solution 202 is referred to as Option 2 (NR SA), solution 203 isreferred to as Option 4, and solution 204 is referred to as NR+NR. Thissolution introduces a new 5G Standalone core altogether and is analtogether new network, thus the cost/investment will be very high. 5GSA needs 5G SA compatible 5G devices which use new 5G Network Adapters(NAs) to communicate with new 5G Packet Core.

Based on this migration path normally taken by operators is as follows:

FIG. 3 shows the migration path which begins with the 4G EPC 300, then5G NSA with EPC 301 then 5G SA option 302.

Most Operators will initially launch 5G with 5G NSA in order to leveragetheir existing investment and launch 5G with minimal disruption tocurrent network. After that introduce 5G SA via option 2 or option 4/7.

Regarding FIG. 4 , and specifically 5G NSA with EPC 301, in the 4GCdeployment option shown in FIG. 4 , no link is required between the 4Gradio 401 and 5G radio 402 with the 4G core 400. Dual connectivity isnot required. Instead, a 5G RAN 402 is coupled to 4GC 400. This isanother NSA deployment option.

FIG. 5 is a system diagram showing an HNG between the 4G core and a 4GRAN and a 5G RAN, in accordance with some embodiments.

As shown in FIG. 5 , a 4G RAN 502 (base station) and a 5G RAN 503 (basestation) can both be coupled to a virtualization server (HNG) 501, andthe HNG can be coupled to the 4G core 500. The HNG includes a virtual 4Gcore 501 a and a virtual 5G core 501 b. The HNG is in communication witha 4G RAN 502 and a 5G RAN 503 by way of respective virtualizingfunctions (VFs). A UE 504 is shown in communication with the 5G RAN. TheHNG can interwork 4G to 5G such that a 5G RAN can work with the 4G coreas needed, to support a standard 5G UE without a 5G standalone core, andcan be switched over to a full 5G core later.

From the UE's perspective, a 5G standalone core is provided. This isbecause a virtual 5G core is created at the HNG. The HNG includesinterworking between the 4G and 5G virtual cores at the HNG. Forexample, QCI is interworked to its equivalent 5G parameter, etc.

A single underlying data store at the HNG supports both the 4G and 5Gvirtual cores (and thus the 4G and 5G RANs). The single data storefacilitates interworking, and the single data store can emit data thatis used either in 4G or 5G signaling as identified by the interworkingat the HNG.

FIG. 6 shows an HNG 601 including a virtual 4G core 601 a and a virtual5G core 601 b communicating by way of an Inter Working Function (IWF)601 c. The HNG is in communication with a 4G core 600. The HNG is alsoin communication with 4G RAN 602. Also shown is a 5G RAN 603 with a UE604. The IWF manages communications between the 4GC 601 a and 5GC 601 b.The IWF enables the UE 604 to couple to 5G RAN 603 and virtual 5G core601 b, but enables the UE to be managed by 4GC 600 via virtual 4GC 601a. The IWF interworks all communications between 601 b and 601 a.Regarding the role of 4GC 601 a and 4GC 600, 4GC 600 is a standard EPCand 4GC 601 a is a virtualizing core that enables multiple base stations(4G or 5G) to be virtualized toward 4GC 600 at the HNG 601.

FIG. 7 shows an HNG 701 including a virtual 4G core 701 a and also avirtual 5G core 701 b communicating by way of an Inter Working Function(IWF) 701 c. The HNG is in communication with a core 700 including a 4Gcore 700 a and a 5G core 700 b. The HNG is also in communication with 4GRAN 702. Also shown is a 5G RAN 703 with a UE 704. The HNG facilitateseither a 4G RAN coupled with the 4G core 700 a, the 5G ran 703 coupledwith 5G core 700 b, the 4G RAN coupled with the 5G core, the 5G RANcoupled with the 4G Core, both 4G and 5G RANs coupled with the 5G core,both the 4G and 5G RANs coupled with the 4G core, etc. The IWF enablesthis by interworking various signaling to and from 4G and 5G, to enablea deployment as desired by the operator.

The embodiments shown in FIGS. 5-7 are not the same as dual connectivitybecause they work with regular 4G RANs, without the need to upgrade to3GPP Rel. 15 and above on the 4G RAN to support dual connectivity. Worksin both greenfield networks (where 5G RANs may be deployed withoutconcern for 4G RANs already in place) and networks where 4G RANs arealready deployed. In some embodiments, this may support dualconnectivity (DC) in the case that the 4G RAN is upgraded to support it.This solution also doesn't require the 4G core to be upgraded.

The 4G and 5G RANs may communicate. This may be via X2, or Xx or Xn, orequivalent, if supported by the two base stations. Of course, if directcommunication is not supported between the 4G and 5G RANs, the HNG canproxy and/or broker these communications as it provides X2 brokeringfunctionality (see US20180242396A1 Mishra et al, hereby incorporated byreference in its entirety).

The UE can be always anchored at the single 4G core, in someembodiments. This solution still supports inter-core handovers to andfrom 4G and 5G core, 4G inter-eNB and intra-RAT handover, handoversbetween 4G radio (virtualized/managed by HNG) and 4G radio (managed byitself, i.e., macro base station). In the case that the handover isbetween a 4G radio and a 4G radio, the UE doesn't need to do anythingspecial, of course. In the case the handover is between a 4G radio and a5G radio or vice versa, the UE is aware that it is an inter-RAT handoverbut all signaling is interworked by the IWF at the HNG.

In some embodiments, inter-RAT handovers can benefit from “sideband”information channels between the 4G and 5G cores. There are twosolutions herein. Firstly, a module can be created between the HNG andthe 4G core to translate the inter-RAT handover to an intra-RAThandover.

Secondly, a “phantom” 5G core network can be created to send informationto the 5G-aware 4G EPC.

FIG. 8 is a schematic network architecture diagram for 3G and other-Gprior art networks. The diagram shows a plurality of “Gs,” including 2G,3G, 4G, 5G and Wi-Fi. 2G is represented by GERAN 101, which includes a2G device 801 a, BTS 801 b, and BSC 801 c. 3G is represented by UTRAN802, which includes a 3G UE 802 a, nodeB 802 b, RNC 802 c, and femtogateway (FGW, which in 3GPP namespace is also known as a Home nodeBGateway or HNBGW) 802 d. 4G is represented by EUTRAN or E-RAN 803, whichincludes an LTE UE 803 a and LTE eNodeB 803 b. Wi-Fi is represented byWi-Fi access network 804, which includes a trusted Wi-Fi access point804 c and an untrusted Wi-Fi access point 804 d. The Wi-Fi devices 804 aand 804 b may access either AP 804 c or 804 d. In the current networkarchitecture, each “G” has a core network. 2G circuit core network 805includes a 2G MSC/VLR; 2G/3G packet core network 806 includes anSGSN/GGSN (for EDGE or UMTS packet traffic); 3G circuit core 807includes a 3G MSC/VLR; 4G circuit core 808 includes an evolved packetcore (EPC); and in some embodiments the Wi-Fi access network may beconnected via an ePDG/TTG using S2a/S2b. Each of these nodes areconnected via a number of different protocols and interfaces, as shown,to other, non-“G”-specific network nodes, such as the SCP 830, the SMSC831, PCRF 832, HLR/HSS 833, Authentication, Authorization, andAccounting server (AAA) 834, and IP Multimedia Subsystem (IMS) 835. AnHeMS/AAA 836 is present in some cases for use by the 3G UTRAN. Thediagram is used to indicate schematically the basic functions of eachnetwork as known to one of skill in the art, and is not intended to beexhaustive. For example, 5G core 817 is shown using a single interfaceto 5G access 816, although in some cases 5G access can be supportedusing dual connectivity or via a non-standalone deployment architecture.

Noteworthy is that the RANs 801, 802, 803, 804 and 836 rely onspecialized core networks 805, 806, 807, 808, 809, 837 but shareessential management databases 830, 831, 832, 833, 834, 835, 838. Morespecifically, for the 2G GERAN, a BSC 801 c is required for Abiscompatibility with BTS 801 b, while for the 3G UTRAN, an RNC 802 c isrequired for Iub compatibility and an FGW 802 d is required for Iuhcompatibility. These core network functions are separate because eachRAT uses different methods and techniques. On the right side of thediagram are disparate functions that are shared by each of the separateRAT core networks. These shared functions include, e.g., PCRF policyfunctions, AAA authentication functions, and the like. Letters on thelines indicate well-defined interfaces and protocols for communicationbetween the identified nodes.

The system may include 5G equipment. 5G networks are digital cellularnetworks, in which the service area covered by providers is divided intoa collection of small geographical areas called cells. Analog signalsrepresenting sounds and images are digitized in the phone, converted byan analog to digital converter and transmitted as a stream of bits. Allthe 5G wireless devices in a cell communicate by radio waves with alocal antenna array and low power automated transceiver (transmitter andreceiver) in the cell, over frequency channels assigned by thetransceiver from a common pool of frequencies, which are reused ingeographically separated cells. The local antennas are connected withthe telephone network and the Internet by a high bandwidth optical fiberor wireless backhaul connection.

5G uses millimeter waves which have shorter range than microwaves,therefore the cells are limited to smaller size. Millimeter waveantennas are smaller than the large antennas used in previous cellularnetworks. They are only a few inches (several centimeters) long. Anothertechnique used for increasing the data rate is massive MIMO(multiple-input multiple-output). Each cell will have multiple antennascommunicating with the wireless device, received by multiple antennas inthe device, thus multiple bitstreams of data will be transmittedsimultaneously, in parallel. In a technique called beamforming the basestation computer will continuously calculate the best route for radiowaves to reach each wireless device, and will organize multiple antennasto work together as phased arrays to create beams of millimeter waves toreach the device.

FIG. 9 shows an enhanced eNodeB for performing the methods describedherein, in accordance with some embodiments. eNodeB 900 may includeprocessor 902, processor memory 904 in communication with the processor,baseband processor 906, and baseband processor memory 908 incommunication with the baseband processor. Mesh network node 900 mayalso include first radio transceiver 912 and second radio transceiver914, internal universal serial bus (USB) port 916, and subscriberinformation module card (SIM card) 918 coupled to USB port 916. In someembodiments, the second radio transceiver 914 itself may be coupled toUSB port 916, and communications from the baseband processor may bepassed through USB port 916. The second radio transceiver may be usedfor wirelessly backhauling eNodeB 900.

Processor 902 and baseband processor 906 are in communication with oneanother. Processor 902 may perform routing functions, and may determineif/when a switch in network configuration is needed. Baseband processor906 may generate and receive radio signals for both radio transceivers912 and 914, based on instructions from processor 902. In someembodiments, processors 902 and 906 may be on the same physical logicboard. In other embodiments, they may be on separate logic boards.

Processor 902 may identify the appropriate network configuration, andmay perform routing of packets from one network interface to anotheraccordingly. Processor 902 may use memory 904, in particular to store arouting table to be used for routing packets. Baseband processor 906 mayperform operations to generate the radio frequency signals fortransmission or retransmission by both transceivers 910 and 912.Baseband processor 906 may also perform operations to decode signalsreceived by transceivers 912 and 914. Baseband processor 906 may usememory 908 to perform these tasks.

The first radio transceiver 912 may be a radio transceiver capable ofproviding LTE eNodeB functionality, and may be capable of higher powerand multi-channel OFDMA. The second radio transceiver 914 may be a radiotransceiver capable of providing LTE UE functionality. Both transceivers912 and 914 may be capable of receiving and transmitting on one or moreLTE bands. In some embodiments, either or both of transceivers 912 and914 may be capable of providing both LTE eNodeB and LTE UEfunctionality. Transceiver 912 may be coupled to processor 902 via aPeripheral Component Interconnect-Express (PCI-E) bus, and/or via adaughtercard. As transceiver 914 is for providing LTE UE functionality,in effect emulating a user equipment, it may be connected via the sameor different PCI-E bus, or by a USB bus, and may also be coupled to SIMcard 918. First transceiver 912 may be coupled to first radio frequency(RF) chain (filter, amplifier, antenna) 922, and second transceiver 914may be coupled to second RF chain (filter, amplifier, antenna) 924.

SIM card 918 may provide information required for authenticating thesimulated UE to the evolved packet core (EPC). When no access to anoperator EPC is available, a local EPC may be used, or another local EPCon the network may be used. This information may be stored within theSIM card, and may include one or more of an international mobileequipment identity (IMEI), international mobile subscriber identity(IMSI), or other parameter needed to identify a UE. Special parametersmay also be stored in the SIM card or provided by the processor duringprocessing to identify to a target eNodeB that device 900 is not anordinary UE but instead is a special UE for providing backhaul to device900.

Wired backhaul or wireless backhaul may be used. Wired backhaul may bean Ethernet-based backhaul (including Gigabit Ethernet), or afiber-optic backhaul connection, or a cable-based backhaul connection,in some embodiments. Additionally, wireless backhaul may be provided inaddition to wireless transceivers 912 and 914, which may be Wi-Fi802.11a/b/g/n/ac/ad/ah, Bluetooth, ZigBee, microwave (includingline-of-sight microwave), or another wireless backhaul connection. Anyof the wired and wireless connections described herein may be usedflexibly for either access (providing a network connection to UEs) orbackhaul (providing a mesh link or providing a link to a gateway or corenetwork), according to identified network conditions and needs, and maybe under the control of processor 902 for reconfiguration.

A GPS module 930 may also be included, and may be in communication witha GPS antenna 932 for providing GPS coordinates, as described herein.When mounted in a vehicle, the GPS antenna may be located on theexterior of the vehicle pointing upward, for receiving signals fromoverhead without being blocked by the bulk of the vehicle or the skin ofthe vehicle. Automatic neighbor relations (ANR) module 932 may also bepresent and may run on processor 902 or on another processor, or may belocated within another device, according to the methods and proceduresdescribed herein.

Other elements and/or modules may also be included, such as a homeeNodeB, a local gateway (LGW), a self-organizing network (SON) module,or another module. Additional radio amplifiers, radio transceiversand/or wired network connections may also be included.

FIG. 10 shows a coordinating server for providing services andperforming methods as described herein, in accordance with someembodiments. Coordinating server 600 includes processor 1002 and memory1004, which are configured to provide the functions described herein.Also present are radio access network coordination/routing (RANCoordination and routing) module 1006, including ANR module 1006 a, RANconfiguration module 1008, and RAN proxying module 1010. The ANR module1006 a may perform the ANR tracking, PCI disambiguation, ECGIrequesting, and GPS coalescing and tracking as described herein, incoordination with RAN coordination module 1006 (e.g., for requestingECGIs, etc.). In some embodiments, coordinating server 1000 maycoordinate multiple RANs using coordination module 1006. In someembodiments, coordination server may also provide proxying, routingvirtualization and RAN virtualization, via modules 1010 and 1008. Insome embodiments, a downstream network interface 1012 is provided forinterfacing with the RANs, which may be a radio interface (e.g., LTE),and an upstream network interface 1014 is provided for interfacing withthe core network, which may be either a radio interface (e.g., LTE) or awired interface (e.g., Ethernet).

Coordinator 1000 includes local evolved packet core (EPC) module 1020,for authenticating users, storing and caching priority profileinformation, and performing other EPC-dependent functions when nobackhaul link is available. Local EPC 1020 may include local HSS 1022,local MME 1024, local SGW 1026, and local PGW 1028, as well as othermodules. Local EPC 1020 may incorporate these modules as softwaremodules, processes, or containers. Local EPC 1020 may alternativelyincorporate these modules as a small number of monolithic softwareprocesses. Modules 1006, 1008, 1010 and local EPC 1020 may each run onprocessor 1002 or on another processor, or may be located within anotherdevice.

In any of the scenarios described herein, where processing may beperformed at the cell, the processing may also be performed incoordination with a cloud coordination server. A mesh node may be aneNodeB. An eNodeB may be in communication with the cloud coordinationserver via an X2 protocol connection, or another connection. The eNodeBmay perform inter-cell coordination via the cloud communication server,when other cells are in communication with the cloud coordinationserver. The eNodeB may communicate with the cloud coordination server todetermine whether the UE has the ability to support a handover to Wi-Fi,e.g., in a heterogeneous network.

Although the methods above are described as separate embodiments, one ofskill in the art would understand that it would be possible anddesirable to combine several of the above methods into a singleembodiment, or to combine disparate methods into a single embodiment.For example, all of the above methods could be combined. In thescenarios where multiple embodiments are described, the methods could becombined in sequential order, or in various orders as necessary.

Although the above systems and methods for providing interferencemitigation are described in reference to the Long Term Evolution (LTE)standard, one of skill in the art would understand that these systemsand methods could be adapted for use with other wireless standards orversions thereof. The inventors have understood and appreciated that thepresent disclosure could be used in conjunction with various networkarchitectures and technologies. Wherever a 4G technology is described,the inventors have understood that other RATs have similar equivalents,such as a gNodeB for 5G equivalent of eNB. Wherever an MME is described,the MME could be a 3G RNC or a 5G AMF/SMF. Additionally, wherever an MMEis described, any other node in the core network could be managed inmuch the same way or in an equivalent or analogous way, for example,multiple connections to 4G EPC PGWs or SGWs, or any other node for anyother RAT, could be periodically evaluated for health and otherwisemonitored, and the other aspects of the present disclosure could be madeto apply, in a way that would be understood by one having skill in theart.

Additionally, the inventors have understood and appreciated that it isadvantageous to perform certain functions at a coordination server, suchas the Parallel Wireless HetNet Gateway, which performs virtualizationof the RAN towards the core and vice versa, so that the core functionsmay be statefully proxied through the coordination server to enable theRAN to have reduced complexity. Therefore, at least four scenarios aredescribed: (1) the selection of an MME or core node at the base station;(2) the selection of an MME or core node at a coordinating server suchas a virtual radio network controller gateway (VRNCGW); (3) theselection of an MME or core node at the base station that is connectedto a 5G-capable core network (either a 5G core network in a 5Gstandalone configuration, or a 4G core network in 5G non-standaloneconfiguration); (4) the selection of an MME or core node at acoordinating server that is connected to a 5G-capable core network(either 5G SA or NSA). In some embodiments, the core network RAT isobscured or virtualized towards the RAN such that the coordinationserver and not the base station is performing the functions describedherein, e.g., the health management functions, to ensure that the RAN isalways connected to an appropriate core network node. Differentprotocols other than S1AP, or the same protocol, could be used, in someembodiments.

In some embodiments, the software needed for implementing the methodsand procedures described herein may be implemented in a high levelprocedural or an object-oriented language such as C, C++, C#, Python,Java, or Perl. The software may also be implemented in assembly languageif desired. Packet processing implemented in a network device caninclude any processing determined by the context. For example, packetprocessing may involve high-level data link control (HDLC) framing,header compression, and/or encryption. In some embodiments, softwarethat, when executed, causes a device to perform the methods describedherein may be stored on a computer-readable medium such as read-onlymemory (ROM), programmable-read-only memory (PROM), electricallyerasable programmable-read-only memory (EEPROM), flash memory, or amagnetic disk that is readable by a general or specialpurpose-processing unit to perform the processes described in thisdocument. The processors can include any microprocessor (single ormultiple core), system on chip (SoC), microcontroller, digital signalprocessor (DSP), graphics processing unit (GPU), or any other integratedcircuit capable of processing instructions such as an x86microprocessor.

In some embodiments, the radio transceivers described herein may be basestations compatible with a Long Term Evolution (LTE) radio transmissionprotocol or air interface. The LTE-compatible base stations may beeNodeBs. In addition to supporting the LTE protocol, the base stationsmay also support other air interfaces, such as UMTS/HSPA, CDMA/CDMA2000,GSM/EDGE, GPRS, EVDO, 2G, 3G, 5G, TDD, or other air interfaces used formobile telephony.

In some embodiments, the base stations described herein may supportWi-Fi air interfaces, which may include one or more of IEEE802.11a/b/g/n/ac/af/p/h. In some embodiments, the base stationsdescribed herein may support IEEE 802.16 (WiMAX), to LTE transmissionsin unlicensed frequency bands (e.g., LTE-U, Licensed Access or LA-LTE),to LTE transmissions using dynamic spectrum access (DSA), to radiotransceivers for ZigBee, Bluetooth, or other radio frequency protocols,or other air interfaces.

The foregoing discussion discloses and describes merely exemplaryembodiments of the present invention. In some embodiments, softwarethat, when executed, causes a device to perform the methods describedherein may be stored on a computer-readable medium such as a computermemory storage device, a hard disk, a flash drive, an optical disc, orthe like. As will be understood by those skilled in the art, the presentinvention may be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. For example, wirelessnetwork topology can also apply to wired networks, optical networks, andthe like. The methods may apply to LTE-compatible networks, toUMTS-compatible networks, or to networks for additional protocols thatutilize radio frequency data transmission. Various components in thedevices described herein may be added, removed, split across differentdevices, combined onto a single device, or substituted with those havingthe same or similar functionality.

Although the present disclosure has been described and illustrated inthe foregoing example embodiments, it is understood that the presentdisclosure has been made only by way of example, and that numerouschanges in the details of implementation of the disclosure may be madewithout departing from the spirit and scope of the disclosure, which islimited only by the claims which follow. Various components in thedevices described herein may be added, removed, or substituted withthose having the same or similar functionality. Various steps asdescribed in the figures and specification may be added or removed fromthe processes described herein, and the steps described may be performedin an alternative order, consistent with the spirit of the invention.Features of one embodiment may be used in another embodiment.

1. A virtualizing and interworking gateway, comprising: a virtual 4G core; a virtual 5G core; an interface to a core network; an interface to a 4G Radio Access Network (RAN); and an interface to a 5G RAN; wherein the virtualizing and interworking gateway provides interworking 4G to 5G such that a 5G RAN works with a 4G core.
 2. The virtualizing and interworking gateway of claim 1, further comprising a data store supporting the virtual 4G core and the virtual 5G core.
 3. The virtualizing and interworking gateway of claim 1 further comprising an Interworking Function (IWF) and wherein the IWF interworks signaling between the 4G virtual core and 5G virtual core.
 4. The virtualizing and interworking gateway of claim 1 wherein inter-Radio Access Technology (RAT) handovers use sideband information channels between the virtual 4G core and the virtual 5G core.
 5. The virtualizing and interworking gateway of claim 4 wherein the inter-RAT handovers use a module defined between the virtualizing and interworking gateway and the 4G core to translate the inter-RAT handover to an intra-RAT handover.
 6. The virtualizing and interworking gateway of claim 4 wherein the inter-RAT handovers use a phantom 5G core network to send information to the 5G-aware 4G evolved packet core (EPC).
 7. A method for 4G and 5G core interworking, comprising: providing a HetNet gateway (HNG), the HNG comprising: a virtual 4G core; a virtual 5G core; an interface to a core network; an interface to a 4G Radio Access Network (RAN); and an interface to a 5G RAN; and interworking, by the HNG, 4G to 5G such that a 5G RAN works with a 4G core.
 8. The method of claim 7, further comprising supporting, by a data store of the HNG, the virtual 4G core and the virtual 5G core.
 9. The method of claim 7 further comprising interworking signaling between the 4G virtual core and 5G virtual core by an Interworking Function (IWF).
 10. The method of claim 7 further comprising using sideband information channels for inter-Radio Access Technology (RAT) handovers between the virtual 4G core and the virtual 5G core.
 11. The HNG method of claim 10 further comprising using a module defined between the HNG and the 4G core to translate the inter-RAT handover to an intra-RAT handover.
 12. The method of claim 10 further comprising using a phantom 5G core network to send information to the 5G-aware 4G evolved packet core (EPC) for inter-RAT handovers.
 13. A non-transitory computer-readable medium containing instructions for 4G and 5G core interworking, which, when executed, cause a HetNet Gateway (HNG) perform steps comprising: providing a virtual 4G core, a virtual 5G core, an interface to a core network, an interface to a 4G Radio Access Network (RAN), and an interface to a 5G RAN; and providing interworking 4G to 5G such that a 5G RAN works with a 4G core.
 14. The computer-readable medium of claim 13, further comprising instructions for providing a data store supporting the virtual 4G core and the virtual 5G core.
 15. The computer-readable medium of claim 13 further comprising instructions for providing an Interworking Function (IWF) and wherein the IWF interworks signaling between the 4G virtual core and 5G virtual core.
 16. The computer-readable medium of claim 13 further comprising instructions wherein inter-Radio Access Technology (RAT) handovers use sideband information channels between the virtual 4G core and the virtual 5G core.
 17. The computer-readable medium of claim 16 further comprising instructions wherein the inter-RAT handovers use a module defined between the HNG and the 4G core to translate the inter-RAT handover to an intra-RAT handover.
 18. The computer-readable medium of claim 16 further comprising instructions wherein the inter-RAT handovers use a phantom 5G core network to send information to the 5G-aware 4G evolved packet core (EPC). 